Recently, a higher responsiveness and a higher integration of integrated circuits used for electronic devices such as computers have been in greater demand. Accordingly, the power consumption of an integrated circuit has been increased, and the temperature of the electronic component in operation has been increased accordingly. In order to cool the electronic component, a radiating device such as a heat sink has been used.
FIG. 16 shows a conventional radiating device 2 placed on a semiconductor integrated circuit package 1. The radiating device 2 includes a thin rectangular base plate 3 which is in surface-contact with the top surface of the semiconductor integrated circuit package 1, and a number of pins 4 erected on the top surface of the base plate 3 so as to increase the surface area of the radiating device. Typically, the radiating device 2 is formed of aluminum. The heat of the semiconductor integrated circuit package 1 is transmitted to the radiating device 2, and is radiated to the atmosphere from the surface of the radiating device 2.
FIG. 17 shows a conventional fin type radiating device 5. The radiating device 5 includes a circular base plate 6 which is in surface-contact with the top surface of the semiconductor integrated circuit package, and a plurality of fins 7 erected on the top surface of the base plate 6 so as to increase the surface area of the radiating device. Typically, the radiating device 5 of this type is also formed of aluminum.
In the conventional radiating device such as shown in FIGS. 16 and 17, the effect of radiation is improved by increasing the surface area. However, such conventional devices do not provide a satisfactory effect when used with modern electronic components having a higher responsiveness and a higher integration.
A heat pipe has been known as another example of a radiating device for cooling an electronic component. A heat pipe is obtained by reducing the inner pressure in an air tight container formed by closing both ends of a pipe, and by sealing a heat carrier such as water or alcohol, which is called a working fluid in the pipe. At a heated portion of the heat pipe, the fluid turns to steam or gas, the gas radiates heat when it moves away from the heated portion, and again turns into liquid. The liquid returns to the heated portion because of capillary action. The heat is transmitted from the heated portion to the radiating portion by the repetition of this phenomenon.
A heat pipe is placed on a top surface of an electronic component in order to cool the electronic component such as a semiconductor integrated circuit package. Since the heat pipe is linearly in contact with the electronic component, the efficiency of the heat transmission from the electronic component to the heat pipe is not good.